The present invention relates to an X-ray radiographing system having a spot-film device transporting an X-ray sheet film between a fluoroscopic area and a radiographing area and, in particular, to an X-ray radiographing system which enables to enlarge a longitudinal (used in the meaning of "in the direction of a body axis of a patient (an axis going through the head and toe of a patient)" hereinafter) radiographic range along a body axis of a patient.
An X-ray radiographing system disposed in a radiographing chamber is provided with an X-ray generator, and a table which includes a spot-film device inside and a tabletop on the top side on which a patient lies down. Owing to an adequate drive and holder, the X-ray generator and the spot-film device move synchronously (i.e. keeping the same position along the X-ray proceeding direction, here in this specification) and longitudinally, facing each other with the patient on the tabletop therebetween.
While a fluoroscopic area and a radiographic area between which a film holder holding an X-ray sheet film shuttles are arranged each other longitudinally inside the spot-film device, the film holder is transported for radiographing the patient from the fluoroscopic area to the radiographic area. The X-ray sheet film is exposed at the radiographic area by the X-ray which has been radiated by the X-ray generator and penetrated the patient. Normally, the X-ray radiographic system includes an image intensifier (abbreviated as "I.I." hereinafter), a television camera and an X-ray television monitor, costituting an X-ray television system.
The X-ray which has penetrated the patient enters the I.I. through the radioraphic area when the film holder is located at the fluoroscopic area. The I.I. transduces the incident X-ray to a fluorescent light and outputs this fluorescent light to the television camera. The television camera generally has a CCD (Charge Coupled Device) loaded, and the CCD transduces the incident fluorescent light to an electric video signal. The video signal generated at the CCD gets input to the X-ray television monitor. An operator of the X-ray radiographing system can observe an image of the X-ray-radiated part of the patient on a screen of the X-ray television monitor.
If the operator gets the image of the part suitable to radiograph on the screen of the X-ray television monitor, he can transport the film holder to the radiographic area and radiograph this part on the XS-ray sheet film.
The X-ray sheet films to be exposed (unexposed X-ray sheet films) are piled up and stored within a feed magazine inside the spot-film device and are fed to the film holder at the fluoroscopic area through a gap between the rubber rollers clamped each other by pulling springs, before radiographing. On the other hand, the exposed X-ray sheet films are also fed through a gap between the same rubber rollers to a take-up magazine inside the spot-film device. During this feeding process of the unexposed X-ray sheet film, a suction-cup mechanism is commonly used for feeding the unexposed X-ray sheet film from the feed magazine to the rubber rollers.
In the above-mentioned X-ray radiographing system, a large-sized X-ray picture can be taken by using an X-ray film cassette (simply called "cassette" hereinafter), if necessary. In this case, the operator who once has loaded X-ray sheet film to the film holder and operates a console for functioning this X-ray radiographing system outside the radiographing chamber, avoiding X-ray exposure, reenters the radiographing chamber and exchanges the film holder and the cassette holder holding the cassette at the spot-film device.
In the above-mentioned X-ray radiographing system, however, when an economical life-size table whose longitudinal ends coincide with the top of the head and the toe of a patient, respectively, is employed, the moving range of both the radiographic area and fluoroscopic area, which move longitudinally following the travel of the spot-film device, is contracted while these areas are supposed to cover the top of the head through the toe of the patient.
Because the spot-film device contained inside the table only travels within both of the longitudinal ends of the table, the film holder which shuttles longitudinally between both areas cannot transfer entirely to cover the top of the head through the toe of the patient. If the radiographic area covers the top of the head for example at one longitudinal end, then this radiographic area cannot cover the toe at the other longitudinal end, which are covered by the fluoroscopic area. In other words, the operator is unable to carry out the fluoroscopy and radiography concerning the toe of the patient positioned at one end of the table.
Therefore, on one hand, if the economical compact table is employed, the diagnostic range with regard to the whole-body radiography is restricted and insufficient. On the other hand, the table becomes large and costly, so as to acquire a sufficient diagnostic range regarding the whole-body radiography.
In another viewpoint, when the atmosphere surrounding X-ray sheet films piled up and stored within the feed magazine and take-up magazine becomes moist, the emulsifying agent coated on the X-ray sheet films gets sticky and causes the adjacent X-ray sheet films to adhere each other. On the contrary, the excessive dryness causes various troubles in the operation of the X-ray radiographing system. So far, a radiographing chamber has been equipped with both of a moistener and dryer in order to keep the moisture appropriate to operate the X-ray radiographing system.
The moistener and dryer, however, cannot necessarily control the moisture inside the spot-film device. Furthermore, the moistener and dryer require a water-supplier and drainage, respectively, and end up costly.
In a further viewpoint, the each opening of the feed magazine and take-up magazine contained in the spot-film device is covered by a shutter plate when unused, and opened by sliding and pushing the shutter plate out of the spot-film device when the X-ray sheet film gets pulled out and pushed in therethrough. The shutter plate pushed out of the spot-film device, however, hinders the operator from walking around the table containing the spot-film device for the operation.
In addition, the rubber rollers clamped by the pulling springs, which feed the X-ray sheet films through their gaps, are very hard to keep these gaps constant, due to the change of spring force. For this reason, the gaps of the rubber rollers come to have the different distance at the both sides. As a result, the X-ray sheet film going through these gaps happens to slip out of the due course because of the inequal friction at the both sides of the gaps, and to get loaded to the film holder inaccurately.
Lastly, the prior suction-cup mechanism mentioned before uses the horizontal chain for transferring the suction cups which have sucked the X-ray sheet film toward the rubber rollers to feed the X-ray sheet films. This horizontal chain requires considerable space inside the spot-film device, thus making the spot-film device large and uneconomical.